Ultraviolet irradiation apparatuses have been used for general purposes, including fluorescence reaction observations in the fields of, for example, medicine and biotechnology, disinfection, the adhesion of electronic components, and the curing of ultraviolet cure resin and ink. For example, a high-pressure mercury lamp and a metal halide lamp are used as lamp light sources for an ultraviolet irradiation apparatus for use in, for example, the curing of ultraviolet cure resin used for the adhesion of a miniaturized component in, for example, the electronic component field, and the curing of ultraviolet curable ink used in the printing field.
In recent years, global environmental load reduction has been sought after on a worldwide basis, and this trend has led to an aggressive adoption of an ultraviolet light-emitting element, which has a relatively long service life expectancy, achieves energy savings, and is capable of reduction in ozone generation, as a lamp light source.
However, even if an ultraviolet light-emitting element which is capable of relatively successful reduction in heat generation is used as a lamp light source in an ultraviolet irradiation apparatus, depending on usage, heat liberated by the ultraviolet irradiation apparatus may cause a trouble such as a decline in the efficiency of emission of light from the ultraviolet light-emitting element, or shortening of the life expectancy of the ultraviolet light-emitting element. In this regard, for example, as disclosed in Patent Literature 1, a device for cooling ultraviolet irradiation apparatuses is proposed.
However, for example, when a printing apparatus incorporating such an ultraviolet irradiation apparatus which is thus long and large-sized is used, maintenance operation, such as replacement of an ultraviolet light-emitting element, has to be carried out after dismounting of the ultraviolet irradiation apparatus as a whole, which results in poor maintainability.